Commercially available hermetic compressors, including scroll and rotary types, have cylindrical shells with one or more end caps which are attached to the cylindrical shell by welding. The top end cap of a low side hermetic scroll compressor defines, in part, the discharge plenum and may have structure such as a muffler, separator plate, discharge check valve, etc. located therein. The bottom end cap, if present, typically defines the oil sump. In the case of a horizontal compressor, the sump is at least partially located within the cylindrical shell. In order to maximize the internal volume while maintaining minimum size, the end shells have a cylindrical portion and are typically flattened off with a relatively large spherical radius. This design is exemplified by commonly assigned U.S. Pat. No. 4,946,361 which also shows the presence of a cylindrical portion as a location of the radial discharge line. The end cap thus has a first cylindrical portion, an ess shaped transition that provides a shoulder and transitions into a second, smaller diameter cylindrical portion and a large, spherically radiused, relatively flat circular area. The essentially flat, circular area, if mechanically excited to resonance by vibration or pressure pulsation, can act as a drumhead and become a significant and objectionable radiator of sound.